This invention is directed to polygon box tools and more particularly to polygon box tools which make use of a rotatably mounted milling cutter where hardness of metal or the clearance angle of the tool required to make a specific contour make milling desirable.
The invention pertains to a cam operated polygon tool in combination with a milling cutter to contour different shapes by use of an automatic screw machine. It is well known that many parts used in industry are made of bar stock and turned to shape and size before cutting off in an Automatic Screw Machine. This is done because these machines have 4-6 or 8 spindles and may be performing the operations of drilling, tapping, reaming, turning, forming, etc. simultaneously thus producing workpieces at low cost.
Very often these parts need additional milling or contouring operations to complete the workpiece and this is done as a secondary operation, such as milling a flat, or other shapes, on a conventional milling machine. This secondary operation often takes more time than the first Automatic Screw Machine operation and is expensive.
Some attempts to finish the workpieces on an Automatic Screw Machine by using Polygon Box Tools to turn flats, contours, etc. have been made. These tools such as described in U.S. Pat. No. 3,813,969 have been made with heavy reciprocating parts and the whole operation has been slowed to the speed at which the Polygon Box Tools would operate. The results have been fewer parts completely machined, thus showing little overall savings. This invention is an improvement over U.S. Pat. No. 3,813,969 which overcomes the drawbacks found in the patented device and which permits operation of the polygon box tool at the speed of the driving machine such as a screw machine for milling flats or other shapes.
Additionally, polygon box tools have been provided in which the cam used to actuate the reciprocating parts has been a simple cam capable of moving the parts in one direction only and relying on spring pressure to move the reciprocating parts back in the other direction. Such designs limit the operating speed to the spring pressure capable of maintaining the cam follower in contact with the cam face. Such a device is found in U.S. Pat. No. 3,511,121.